In vivo adaptation of regenerant plants of Fragaria vesca L. cultivars

Purpose. The adaptation of regenerant plants to environmental conditions is the final stage of micropropagation. According to a number of authors, when in vitro plants are transferred to in vivo non-sterile conditions, a significant percentage of mortality is recorded. In a previous publication, the regenerative capacity of strawberry (Fragaria vesca L.) in vitro tissues on MS culture medium (Murashige & Skoog, 1962) and a regenerants was obtained (Chornobrov O. Yu., 2019). The objective of the study is to develop an optimal protocol of acclimation of in vitro F. vesca plants to in vivo conditions. Methods. Biotechnological and statistical methods of research were applied. For the research ‘Ruiana’ and ‘Zhovte Dyvo’ cultivars were used with in vitro cultivation cycle of 30–35 days. Prepared plants were planted in 0.33 L plastic contai ners, one piece in a mixture of coconut substrate and perlite (3:1). Plants were kept under high relative humidity (85–90%) conditions for 3–5 days, 6–8 days and 10–14 days. The studies were carried out in the Plant Biotechnology Laboratory of SS of NULES of Ukraine “BFRS” during 2019–2020. Results. The duration of Fragaria vesca regenerant plants exposure in conditions of high relative humidity significantly affected adaptation efficiency. The proportion of ‘Ruiana’ and ‘Zhovte Dyvo’ plants adapted to the greenhouse conditions were 47.6 ± 2.5% and 60.0 ± 1.7%, respectively, when the plants were kept for 10–14 days. A significant efficiency of plant adaptation (more than 70%) was obtained under condition of preliminarily exposure the roots of the plants in an auxin solution for 25–30 minutes with daily application of 30% solution of glycerine as foliar spray. The plants adapted to the greenhouse conditions had pigmentation characteristic of the variety, without signs of chlorosis and vitrification. Conclusions. An optimal protocol for in vitro adaptation of F. vesca cultivars to in vivo conditions was developed and viable plants were obtained. Further research will be aimed at studying the growth and development of F. vesca regenerant plants in open ground.